HTTP binding spec

Detailed documentation on the HTTP binding component

Setup Dapr component

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: <NAME>
spec:
  type: bindings.http
  version: v1
  metadata:
  - name: url
    value: http://something.com

Spec metadata fields

Binding support

This component supports output binding with the following HTTP methods/verbs:

• create : For backward compatibility and treated like a post
• get : Read data/records
• head : Identical to get except that the server does not return a response body
• post : Typically used to create records or send commands
• put : Update data/records
• patch : Sometimes used to update a subset of fields of a record
• delete : Delete a data/record
• options : Requests for information about the communication options available (not commonly used)
• trace : Used to invoke a remote, application-layer loop- back of the request message (not commonly used)

Request

Operation metadata fields

All of the operations above support the following metadata fields

Retrieving data

To retrieve data from the HTTP endpoint, invoke the HTTP binding with a GET method and the following JSON body:

{
  "operation": "get"
}

Optionally, a path can be specified to interact with resource URIs:

{
  "operation": "get",
  "metadata": {
    "path": "/things/1234"
  }
}

Response

The response body contains the data returned by the HTTP endpoint. The data field contains the HTTP response body as a byte slice (Base64 encoded via curl). The metadata field contains:

Example

Requesting the base URL

• Windows
• Linux

curl -d "{ \"operation\": \"get\" }" \
      http://localhost:<dapr-port>/v1.0/bindings/<binding-name>

curl -d '{ "operation": "get" }' \
      http://localhost:<dapr-port>/v1.0/bindings/<binding-name>

Requesting a specific path

• Windows
• Linux

curl -d "{ \"operation\": \"get\", \"metadata\": { \"path\": \"/things/1234\" } }" \
      http://localhost:<dapr-port>/v1.0/bindings/<binding-name>

curl -d '{ "operation": "get", "metadata": { "path": "/things/1234" } }' \
      http://localhost:<dapr-port>/v1.0/bindings/<binding-name>

Sending and updating data

To send data to the HTTP endpoint, invoke the HTTP binding with a POST, PUT, or PATCH method and the following JSON body:

Note

Any metadata field that starts with a capital letter is passed as a request header. For example, the default content type is application/json; charset=utf-8. This can be overridden be setting the Content-Type metadata field.

{
  "operation": "post",
  "data": "content (default is JSON)",
  "metadata": {
    "path": "/things",
    "Content-Type": "application/json; charset=utf-8"
  }
}

Example

Posting a new record

• Windows
• Linux

curl -d "{ \"operation\": \"post\", \"data\": \"YOUR_BASE_64_CONTENT\", \"metadata\": { \"path\": \"/things\" } }" \
      http://localhost:<dapr-port>/v1.0/bindings/<binding-name>

curl -d '{ "operation": "post", "data": "YOUR_BASE_64_CONTENT", "metadata": { "path": "/things" } }' \
      http://localhost:<dapr-port>/v1.0/bindings/<binding-name>

Using HTTPS

The HTTP binding can also be used with HTTPS endpoints by configuring the Dapr sidecar to trust the server’s SSL certificate.

1. Update the binding URL to use https instead of http.
2. Refer How-To: Install certificates in the Dapr sidecar, to install the SSL certificate in the sidecar.

Example

Update the binding component

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: <NAME>
  namespace: <NAMESPACE>
spec:
  type: bindings.http
  version: v1
  metadata:
  - name: url
    value: https://my-secured-website.com # Use HTTPS

Install the SSL certificate in the sidecar

• Self-Hosted
• Kubernetes

When the sidecar is not running inside a container, the SSL certificate can be directly installed on the host operating system.

Below is an example when the sidecar is running as a container. The SSL certificate is located on the host computer at /tmp/ssl/cert.pem.

version: '3'
services:
  my-app:
    # ...
  dapr-sidecar:
    image: "daprio/daprd:1.8.0"
    command: [
      "./daprd",
     "-app-id", "myapp",
     "-app-port", "3000",
     ]
    volumes:
        - "./components/:/components"
        - "/tmp/ssl/:/certificates" # Mount the certificates folder to the sidecar container at /certificates
    environment:
      - "SSL_CERT_DIR=/certificates" # Set the environment variable to the path of the certificates folder
    depends_on:
      - my-app

The sidecar can read the SSL certificate from a variety of sources. See How-to: Mount Pod volumes to the Dapr sidecar for more. In this example, we store the SSL certificate as a Kubernetes secret.

kubectl create secret generic myapp-cert --from-file /tmp/ssl/cert.pem

The YAML below is an example of the Kubernetes deployment that mounts the above secret to the sidecar and sets SSL_CERT_DIR to install the certificates.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
  namespace: default
  labels:
    app: myapp
spec:
  replicas: 1
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
      annotations:
        dapr.io/enabled: "true"
        dapr.io/app-id: "myapp"
        dapr.io/app-port: "8000"
        dapr.io/volume-mounts: "cert-vol:/certificates" # Mount the certificates folder to the sidecar container at /certificates
        dapr.io/env: "SSL_CERT_DIR=/certificates" # Set the environment variable to the path of the certificates folder
    spec:
      volumes:
        - name: cert-vol
          secret:
            secretName: myapp-cert
...

Invoke the binding securely

• Windows
• Linux

curl -d "{ \"operation\": \"get\" }" \
      https://localhost:<dapr-port>/v1.0/bindings/<binding-name>

curl -d '{ "operation": "get" }' \
      https://localhost:<dapr-port>/v1.0/bindings/<binding-name>

Related links

• Basic schema for a Dapr component
• Bindings building block
• How-To: Trigger application with input binding
• How-To: Use bindings to interface with external resources
• Bindings API reference
• How-To: Install certificates in the Dapr sidecar

Last modified July 28, 2022: Add example for HTTPS binding (#2628) (92cc6c15)